Multiple unit double casing pump



Oct. 1, 1940. A. HOLLANDER MULTIPLE UNIT DOUBLE CASING PUMP Filed Jan.4, 1938. 2 Sheets-Sheet 1 Azaclar Hoflancier.

ATTORNEY Oct. 1, 1940. A. HOLLANDER MULTIPLE UNIT-DOUBLE CASING PUMPFiled Jan. 4, 1938 2 Sheets-Sheet 2 Azada; yozzanaer nvmwl.

INVENTOR ATTORNEY Egg Patented Oct. 1, 1940 UNITED STATES 2,216,315MULTIPLE UNIT DOUBLE CASING PUMP Aladar Hollander, Los Angeles, Calif.,

assignor to Byron Jackson Co., Huntington Park, Calif., a corporationofDelaware Application January 4, 1938, Serial No. 183,298 6 Claims. (Cl.103-108) This invention relates to improvements in multiple stagecentrifugal pumps of the so-called double casing type such as are shownin my prior Patents Nos. 1,655,546 and 1,655,547 issued January 10, 1928and No. 1,997,824 issued April 16, 1935.

Double casing pumps of the type shown in my prior patents arecharacterized by an axially split, multiple-stage inner or pump casingenclosed in an outer casing, the walls of the inner and outer casingsbeing spaced apart to form a fluid receiving chamber, the inner or pumpcasing discharging into the space between the casings, and the outercasing being provided with a discharge outlet communicating with thespace between the casings. This construction places the inner or pumpcasing under compression due to the discharge pressure being admitted tothe space between the two casings. Consequently such pumps can bedesigned for high pressure work but do not require the usual thick heavyWalls that are ordinarily required for withstanding such high pressures.In fact, the walls of these pumps are extremely thin (about threeeighthsof an inch in thickness) in pumps capable of developing several thousandpounds pressure per square inch.

In order to provide double casing pumps capable of producing higherpressures than those shown in my prior patents it has heretofore beencustomary merely to increase the number of stages in the inner or pumpcasing. I have found, however, that there are limits beyond which it isnot practical to merely increase the number of stages. For pumps havingaxially split casings, the practical limit appears to be abouttwenty-two stages in a single casting because it is extremely difiicultif not impossible to obtain satisfactory castings and to machine thecastings with satisfactory alignment when the number of stages exceedsthis figure.

It is characteristic of pumps having axially split casings (unlike pumpshaving radially split casings) that the length of the casing castingsincreases with the number of stages. It is customary to assemble the twohalves of the axially split casing without the use of a gasket. If agasket were used it would have to be extremely thin and would be likelyto blow out. Also, a thin gasket would be destroyed each time the pumpwere taken apart for inspection or repair. When the two halves of thecasingare assembled without a gasket their meeting faces are ground andscraped to insure a fluid-tight fit. With thin walled casings of morethan twenty-two stages it is not practical to use the metal to metalseal because of warpage and flexing. Neither is it practical to use agasket. Nor'is it practical to employ radially split casings, because amultistage pump of this type is too diflicult to assemble anddisassemble and is diflicult to balance hy-' draulically.

The object of the present invention is to provide a construction fordouble casing, multiple stage pumps of the axially split inner casingtype whereby the number of stages can be increased to any desired numberwithout requiring pattern equipment for each size of pump and withoutmaterially complicating the casting or machining practice such as isused for pumps of a lesser number of stages.

Another object is to provide a multi-stage, double casing pump of theaxially split inner casing type wherein the pump is made up of aplurality of separate units comprising a relatively few number of stagesin a single outer case.

Another object is to provide a multi-stage, double casing pump of theaxially split inner casing type having a plurality of separate pumpingunits in a single outer case and wherein at least one of the pumpingunits is a standard unit such as is used in a double casing pump havingonly one pumping unit.

Another object is to provide a multistage, double casing pump of theaxially split inner casing type having a plurality of separate pumpingunits in a single outer case and wherein a relatively few types ofspecial units can be combined to make a large number of different totalpump stages.

Figure 1 illustrates a side view of the invention.

Figures 2 and 2A illustrate an enlarged sectional view through the shaftaxis of a double casing, multi-stage centrifugal pump shown in Fig. 1,Figure 2 showing the upper portion of the pump and Figure 2A showing thelower por- Figure 3 is a cross section of the pump shown in Figs. 2 and2A taken on line 3-3 of Fig. 2A.

The numeral l indicates a tubular seamless steel casing which forms theouter or higher pressure casing of my pump. The inner or pump volutecasing is shown at 2 and 3. The view shown in Fig. 2 is taken on theparting face of the inner casings 2 and 3. The outer casing I is closedat its lower end and is spaced from the inner casing to provide a fluidchamber 5 between the inner and outer casings. The outer casing l isprovided at its upper end with a flange 1 to which the nozzle head 9 isattached by bolts I II. The nozzle head 9 is provided with a laterallyextending suction nozzle l2 whic communicates with the inlet to thefirst stage impeller at the upper end of the inner casing 2. Nozzle head9 is also provided with a laterally extending discharge nozzle l3 whichcommunicates with the space 5 between the inner and outer casings.Nozzle head 9 is also provided with a stuffing box I 5 motor support 16is bolted to the top of the nozzle through which the pump shaft extends.A-

head 8. The motor shaft is indicated at H and is connected to the pumpshaft 18 by means of a coupling IS.

The inner or pump casing is made up of a number of sections or pumpunits bolted together, each unit being a complete multi-stage pump. Thedrawing shows a pump made up of two units. The lower unit 3 may beeither a duplicate of the upper pump unit or it may be a standard typeof .pump having an axially split casing which may have any number ofstages up to 22, which is the present practical limit for a single pump.These standard pump units are each preferably substantially balancedhydraulically. In the present instance the pump unit 3 is, hydraulicallysubstantially balanced by arranging the impellers in two opposed groups.The upper group of impellers (of which the topmost 20 is the suctionentrance to the pump unit 3) have their suction eyes facing upwardlywhile the lower group face downwardly. A throttle bearing 2| isinterposed between the two opposed groups of impellers; and anotherthrottle bearing 4| is placed at the lower end of the pump casing. Thefluid passes serially through each group of impellers. The dischargefrom the lowermost of the upper impellers 22 is conducted through achannel 23 (formed in the meeting faces of the two halves of the casing3) to the suction eye of the lower-most impeller 24 in the lower group.The fluid discharged from the last impeller 26 of the lower group passesout of the pump casing 3 through the discharge outlet 28 into the fluidchamber 5 between the inner and outer casings and thence out of thecasing i through the discharge nozzle H3.

The upper pump unit 2 is of special design and is intended to be usedwith a standard lower unit similar to unit 3. To this end the upper unit'22 comprises a pair of axially split casings provided at their upperends with a suction entrance 3d similar to the upper or suction end 32of pump unit 3. Thus either of the pump units 2 or 3 can be bolted asshown at 33 to the nozzle head d which is of standard design. The pumpunit 2 is a substantially balanced multi-stage pump, being balancedsimilarly to pump unit it by arranging the impellers in two opposedgroups separated by a throttle bearing 3i. Fluid from the suction nozzlei2 enters the first stage impeller 31d and proceeds downwardly seriallythrough the upper group of impellers to the center of the pump, thencethrough channel 35 to the lowermost im peller t5, upwar through thelower group of impellers in series, and thence downwardly throughchannel ill to the suction inlet 32 to the lower pumping unit 3. Thelower end of pump casing 2 is provided with a throttle bearing 3&3. Theupper and lower pump units are bolted together as shown at 3%.

In the drawings the pump shaft is is a single shaft extending throughboth of the pump units 2 and 3. Separate shafts for each pump unit couldbe used but it would then be necessary to couple the shafts togetherwhere the two units are jointed together. The use of a single shaft ismuch to be preferred. Because each of the pump units is substantiallybalanced in itself there will be theoretically no hydraulic thrust to becarried by the motor.

If it is desired to have more than forty-four stages in the pump Iemploy two or more special sections similar to the upper pump unit 2(although rwo or more special sections may be used with a lesser numberof stages.) Because both ends of the special units 2 are identical andbecause each unit is substantially balanced hydraulically they can beconnected together in any order and in any desired number, withinpractical limits. It would be possible to have each oi the separate pumpunits unbalanced with unbalance equal but in opposite directions in eachunit so that the pump as a whole would be balanced. However, such anarrangement would not have the practical advantages of the arrangementshown in the drawings. Also any of the well known balancing devicescould be used but are not necessary with the design shown in thedrawmgs.

I may provide a centering pin 40 for centering, and, if desired, forpartly supporting the inner casings while the pump is being shipped. Thepin 40 is shown in axial alignment with and supporting the pump endbearing 4 i.

For very high pressure pumps I may also. provide means for relieving thehydraulic thrust against the lower end of the shaft Hi. This isaccomplished by venting the throttle bearing ii back to a lower pumpstage through the line 43.

By making use of the construction described above I can build specialservice pumps having any desired number of stages. This is accomplishedwithout the necessity of having diiferent pattern equipment for eachpump. The motor support, nozzle head and lowermost pump unit arestandard lower pressure equipment. The outer casing is seamless steelcasing which is obtainable in any desired length and diameter. Thus theonly special parts are the special upper pump units 2 and only a fewsizes and numbers of stages of these special units are needed in orderto make a large number of combinations with the standard lower units.For example, the standard lower units are regularly made in evennumbered groups of four to twenty-two impellers and in sizes of suctioninlets of 1 3" and 4". The special units are preferably made in units ofsixteen stages in the same three sizes. Thus a pump for delivering 25gallons per minute against a pressure of approximately 1,000 lbs. mayconsist of a standard 1 /2" twenty-two stage lower unit and twoidentical sixteen stage upper units.

The above described construction has the further advantage of requiringno complicated pattern equipment for a pump having a large number ofstages. Also, the casting and machining operations are made as simple asfor a pump having relatively few stages.

I claim:

1. In a multi-stage centrifugal pump, a supporting means having an inletand an outlet therein, a substantially hydraulically balancedmulti-stage centrifugal pump unit having an axially split casing mountedon said support with an inlet in one end thereof in communication withthe inlet in said support and having an outlet in the opposite endthereof, a second substantially hydraulically balanced multi-stagecentrifugal pump unit having an axially split casing secured to andsupported by the discharge and of said first pump unit with an inlet inone end thereof communicating with the outlet from said first pump unit,an outer casing secured to said supporting means and enclosing said pumpunits in spaced relation thereto providing a fluid pressure chamberbetween said pump units and the outer casing in communication with theoutlet in said supporting means, and a discharge opening from saidsecond pump unit communicating with said fluid pressure chamber.

2. In a vertical multi-stage centrifugal pump, a supporting means havingan inlet through the center-thereof, a substantially hydraulicallybalanced multi-stage centrifugal pump unit having an axially split innercasing mounted on said supporting means with its inlet in registry withthe inlet through said supporting means and having a discharge outlet inthe opposite end thereof, said discharge end being symmetrical with theinlet end of said supporting means, a second substantially hydraulicallybalanced multi-stage centrifugal pump unit having an axially split innercasing mounted on and supported by the discharge end of said first pumpunit with its inlet in registry with the outlet therefrom, a singleshaft for both pump units extending through the supporting means, abearing for the other end of said shaft carried by the distal end ofsaid second pump unit, an outer casing mounted on said supporting meansin circumferentially spaced relation to said pump units, said outercasing being free from contact with said pump units, a discharge outletfrom said second pump unit communicating with the space between the pumpunits and the outer casing, and a discharge outlet through saidsupporting means communicating with said space.

3. In a vertical multi-stage centrifugal pump, a supporting memberhaving a suction inlet therein, a substantially hydraulically balancedaxially split multi-stage pump having an inlet at one end and asymmetrical outlet at the opposite end mounted on said supportingmemberwith its pump inlet in registry with the inlet through said supportingmember, a second substantially hydraulically balanced, axially splitmulti-stage pump having a suction inlet at one end adapted to registerwith the outlet from said first pump and adapted to be mounted thereonand be supported thereby, a single shaft for both pumps having one endextending through said supporting member and provided at its other endwith a bearing carried by the distal end of said second pump, an outercasing mounted on said supporting member in circumferentially spacedrelation to said pumps, and being free from contact therewith, adischarge outlet from said second pump communicating with the spacebetween the outer casing and said pumps, and a discharge outlet throughsaid supporting member communicating with said space.

4. In a vertical, multi-stage centrifugal pump, a supporting memberhaving a suction inlet therein, a first substantially hydraulicallybalanced multistage pump having an axially split casing with an inlet atone end and an outlet at its opposite end symmetrical with said inlet,said pump being mounted on said supporting member with its inlet inregistry with the inlet through said supporting member, the impellers insaid pump being arranged in two opposed groups, the group adjacent theinlet having their suction eyes facing toward said inlet and the opposedgroup having their suction eyes facing in the opposite direction, athrottle bearing between the two groups of impellers, a secondsubstantially hydraulically balanced multi-stage pump having an axiallysplit casing with an inlet at one end adapted to be mounted on andregister with the outlet from said first pump, a throttle bearingbetween the inlet of the second pump and the adjacent group of impellersof the first pump. said second pump having the impellers thereinarranged in two opposed groups, the group adjacent the inlet end havingtheir suction eyes fac- 5 ing toward said inlet and the opposed grouphaving their suction eyes facing in the opposite direction, a singleshaft for both pumps having one end extending through said supportingmember and having its other end terminating within said 10 second pumpcasing at the distal end thereof, a throttle bearing about said shaftbetween the two opposed groups -of impellers, another throttle bearingin the distal end of said second pump casing and defining therewith asubstantially l5 closed chamber for the end of said shaft, and means forventing the pressure from said chamber back to a lower pump stage.

5. In a multi-stage centrifugal pump, a supporting means having asubstantially centrally 20 disposed suction inlet opening therein, asubstantially hydraulically balanced multi-stage centrifugal pump unithaving an axially split casing mounted on said support with a suctioninlet in one end thereof in communication with the inlet 25 opening insaid supporting means and having a discharge outlet at the opposite endsubstantially coaxial with said suction inlet, a second substantiallyhydraulically balanced multi-stage centrifugal pump unit having anaxially split casing 80 supported by the discharge end of said firstpump unit and having a suction inlet registering with the dischargeoutlet from said first pump unit, impeller shafting extending throughsaid inlet opening in said supporting means in substantially 85 coaxialrelation thereto and extending into said pump units, impellers on saidshafting, an outer casing secured to said supporting means and enclosingsaid pump units in spaced relation thereto providing a fluid pressurechamber between said outer casing and said pump units, a dischargeopening from said second pump unit to said fluid pressure chamber, and adischarge outlet from said outer casing communicating with said fluidpressure chamber.

6. In a multiple stage centrifugal pump of the double casing type, asupporting means having an inlet opening therein, a plurality ofmulti-stage pump units having axially split inner pump casings connectedend to end and connected at one end to said supporting means with thesuction inlet of the first unit in registery with the inlet opening insaid supporting means, each pump unit being substantially hydraulicallybalanced by means of opposed groups of impellers and having a throttlebearing between each of the opposed impeller groups and at the distalend of each pump unit, a fluid cross-over channel formed in the partingfaces of each of said casings between the opposed groups of impellerstherein, a fluid channel formed in the parting faces of each of saidcasings leading from the final stage of each of said pump units exceptthe last to the distal end thereof, an outer casing secured to saidsupporting means and enclosing said units in circumferentially spacedrelation thereto, a fluid channel leading from the final stage of saidlast unit to the space between said outer casing and said units, and adischarge outlet from said outer casing communicating with the spacebetween said outer casing and said units.

ALADAR HOILANDER.

czzn'mmcym or conmzonon. Patent No. 2,216,515. October 1, who.

' ALADAR HOLLANDER- It is hereby certified that error appears in theprinted specification of the above numbered patent requiring correctionas follows: Page 5, first column, line 18, claim 2, after the word"units" insert --having one end";-

and that the said Letters Patent should be read with this correctiontherein that the 'same may conform to the record of the case in thePatent Office.

Signed and sealed this 12th day of Novanber, A. D. 1911.0.

Henry Van Arsdele Acting Comnis sioner of Patents.

